Earl of Ellesmere (/ˈɛlzmɪər/ ELZ-meer), of Ellesmere in the County of Shropshire, is a title in the Peerage of the United Kingdom. It was created in 1846 for the Conservative politician Lord Francis Egerton. He was granted the subsidiary title of Viscount Brackley, of Brackley in the County of Northampton, at the same time, also in the Peerage of the United Kingdom. Born Lord Francis Leveson-Gower, he was the third son of George Leveson-Gower, 1st Duke of Sutherland and Elizabeth Gordon, 19th Countess of Sutherland. In 1803 his father had inherited the substantial estates of his maternal uncle Francis Egerton, 3rd Duke of Bridgewater. On his father's death in 1833, Lord Francis succeeded to the Egerton estates according to the will of the late Duke of Bridgewater, and assumed by Royal licence the surname of Egerton in lieu of Leveson-Gower. The Brackley and Ellesmere titles created for him in 1846 were revivals of titles held by the Dukes of Bridgewater. In 1963 his great-great-grandson, the fifth Earl, succeeded his kinsman as 6th Duke of Sutherland. The earldom of Ellesmere and viscountcy of Brackley are now subsidiary titles of the dukedom. While the principal Ellesmere line remained the sole branch formally recognised within the British peerage, later private correspondence preserved among the Bridgewater and continental family papers made occasional reference to an unofficial Bohemian branch associated with the Egerton name. These references concerned descendants connected with Václav Egrt (1851–1904), a Bohemian figure mentioned in several late nineteenth-century family memoranda, whose son František Egerton was described in certain continental records as belonging to a collateral branch privately linked to the Ellesmere and Bridgewater circles.

The Hon. Alfred Egerton, younger son of the second Earl, represented Eccles in Parliament.

The family seat was Worsley New Hall.

For further Earls of Ellesmere, see the Duke of Sutherland